1. Field of the Invention
The present invention relates to heat engines and more particularly to a nitinol powered heat engine which produces a linear output for doing work.
2. Description of the Prior Art
The inventor of the present invention is also the inventor of the Banks Engine, U.S. Pat. No. 3,913,326, for Energy Conversion System, issued Oct. 21, 1975, which was the first proven reliable nitinol engine. The "Background Of The Invention" section of that patent sets forth in part the status of the prior art at the time of that invention. The "Summary of the Invention" section of that patent describes the thermodynamic working material as a thermally responsive memory material, such as nitinol, which is used to power the present invention. The thermally responsive materials which demonstrate these characteristics have come to be known as the shape memory effect class of materials.
Subsequent to the development of the original engine, the present inventor developed an improved version of an engine to extract the tensile energy of straight nitinol wire. That engine is disclosed in the U.S. Pat. No. 4,257,231, for Heat Engine, issued Mar. 24, 1981. The "Background Of The Invention" section of that patent sets forth in part the status of the art which had developed at the time of that invention. The "Summary of the Invention" section of that patent describes the problems with extracting energy from straight wires of nitinol or any other thermally responsive shape memory effect material.
While the Heat Engine patent discloses the first practical machine for extracting energy from straight nitinol wires, the power takeoff mechanism was complicated, arbitrary in the rate and extent of displacement imposed on the nitinol power elements, and ultimately proved difficult in scaling up for useful energy extraction. The machine also had large inertia in the moving parts which limits its speed and contributes to inefficiency of operation.